SERVER-2554 Allow user configuration of the listen depth

4 files changed, 14 insertions, 3 deletions

diff --git a/src/mongo/db/server_options.h b/src/mongo/db/server_options.h
index dcf8c52c293..b4efdde5300 100644
--- a/src/mongo/db/server_options.h
+++ b/src/mongo/db/server_options.h
@@ -53,6 +53,8 @@ struct ServerGlobalParams {
     bool enableIPv6 = false;
     bool rest = false;  // --rest
 
+    int listenBacklog = 0;  // --listenBacklog, real default is SOMAXCONN
+
     bool indexBuildRetry = true;  // --noIndexBuildRetry
 
     AtomicBool quiet{false};  // --quiet
diff --git a/src/mongo/db/server_options_helpers.cpp b/src/mongo/db/server_options_helpers.cpp
index 753acfd38c1..11a4f37008a 100644
--- a/src/mongo/db/server_options_helpers.cpp
+++ b/src/mongo/db/server_options_helpers.cpp
@@ -199,6 +199,11 @@ Status addGeneralServerOptions(moe::OptionSection* options) {
     options->addOptionChaining(
         "net.ipv6", "ipv6", moe::Switch, "enable IPv6 support (disabled by default)");
 
+    options
+        ->addOptionChaining(
+            "net.listenBacklog", "listenBacklog", moe::Int, "set socket listen backlog size")
+        .setDefault(moe::Value(SOMAXCONN));
+
     options->addOptionChaining(
         "net.maxIncomingConnections", "maxConns", moe::Int, maxConnInfoBuilder.str().c_str());
 
@@ -807,6 +812,10 @@ Status storeServerOptions(const moe::Environment& params) {
         enableIPv6();
     }
 
+    if (params.count("net.listenBacklog")) {
+        serverGlobalParams.listenBacklog = params["net.listenBacklog"].as<int>();
+    }
+
     if (params.count("net.transportLayer")) {
         serverGlobalParams.transportLayer = params["net.transportLayer"].as<std::string>();
         if (serverGlobalParams.transportLayer != "asio" &&
diff --git a/src/mongo/transport/transport_layer_asio.cpp b/src/mongo/transport/transport_layer_asio.cpp
index 9751c49eddb..4cf0bafdd2c 100644
--- a/src/mongo/transport/transport_layer_asio.cpp
+++ b/src/mongo/transport/transport_layer_asio.cpp
@@ -262,7 +262,7 @@ Status TransportLayerASIO::start() {
     }
 
     for (auto& acceptor : _acceptors) {
-        acceptor.listen();
+        acceptor.listen(serverGlobalParams.listenBacklog);
         _acceptConnection(acceptor);
     }
 
diff --git a/src/mongo/util/net/listen.cpp b/src/mongo/util/net/listen.cpp
index c4177fda506..74cae6b771b 100644
--- a/src/mongo/util/net/listen.cpp
+++ b/src/mongo/util/net/listen.cpp
@@ -249,7 +249,7 @@ void Listener::initAndListen() {
 
     SOCKET maxfd = 0;  // needed for select()
     for (unsigned i = 0; i < _socks.size(); i++) {
-        if (::listen(_socks[i], SOMAXCONN) != 0) {
+        if (::listen(_socks[i], serverGlobalParams.listenBacklog) != 0) {
             error() << "listen(): listen() failed " << errnoWithDescription();
             return;
         }
@@ -428,7 +428,7 @@ void Listener::initAndListen() {
     }
 
     for (unsigned i = 0; i < _socks.size(); i++) {
-        if (::listen(_socks[i], SOMAXCONN) != 0) {
+        if (::listen(_socks[i], serverGlobalParams.listenBacklog) != 0) {
             error() << "listen(): listen() failed " << errnoWithDescription();
             return;
         }